Host F550 4X4 Motorhome Quad Slide 330

[Wildman]

OK here's how I think it'd be wired if I was using a 5 terminal relay instead of a diode.

Terminal 87 N/O-—--12V Battery Power
Terminal 87A N/C-— Reverse Light 12V
Terminal 30-—————-Camera Power
Terminal 85-—————-Upfitter #2 Switch
Terminal 86-—————-Ground

OK guys.... Let me know if my thought process is correct of not. Had to shake out some braincells and clear out some cobwebs.

 

[lBasket]

OK here's how I think it'd be wired if I was using a 5 terminal relay instead of a diode.

Terminal 87 N/O-—--12V Battery Power
Terminal 87A N/C-— Reverse Light 12V
Terminal 30-—————-Camera Power
Terminal 85-—————-Upfitter #2 Switch
Terminal 86-—————-Ground


View attachment 626861

OK guys.... Let me know if my thought process is correct of not. Had to shake out some braincells and clear out some cobwebs.

You want your camera switch to also turn on your reverse lights?

 

[Wildman]

You want your camera switch to also turn on your reverse lights?

No that is why the reverse lights are on terminal 87A which is N/C but when the relay is energized it becomes N/O.

Or am I missing something?

 

[Wildman]

So I'm curious which of the two ways would all of you opt for?

1) Diode-— Diodes rob a "small" amount voltage but I'm not sure it's an issue in this case. Also they produce a small amount of heat...
2) Relay..... I've got one with a built in fuse left but I'm not sure about having it sitting at the rear of the motorhome. Most likely just use a 5 terminal relay and run with it.

I'm of course open to other options if any of you know of something or of another way to do this?

 

[Zorba]

So I'm curious which of the two ways would all of you opt for?

1) Diode-— Diodes rob a "small" amount voltage but I'm not sure it's an issue in this case. Also they produce a small amount of heat...
2) Relay..... I've got one with a built in fuse left but I'm not sure about having it sitting at the rear of the motorhome. Most likely just use a 5 terminal relay and run with it.

I'm of course open to other options if any of you know of something or of another way to do this?

I'd just do the diode if it were me. Simple, easy, and the .7v drop doesn't matter in this case. Its called a "diode OR" and works well. If you want to be anal, use a diode on both legs, but I don't see that its necessary in this case.

 

[Wildman]

I'd just do the diode if it were me. Simple, easy, and the .7v drop doesn't matter in this case. Its called a "diode OR" and works well. If you want to be anal, use a diode on both legs, but I don't see that its necessary in this case.

OK....

All this is years OLD now for me... Funny that I used to eat & breath this stuff. But it's been too many years.

The relay seems like a more robust way to do it but.

Explain: Why is it called a diode OR? Never heard this term before but then again I'd never heard of a OR gate before until I started looking into this.

I delt with diodes & transistors & resistors: this is the type of symbols I was used to seeing.

 

[Wildman]

These are the diodes I have.

Sufficient for what I'm trying to do?

 

[Zorba]

These are the diodes I have.

View attachment 626887

Sufficient for what I'm trying to do?

Yea - the forward drop is a bit high, but shouldn't be a problem (!!) - you'll have less drop anyway because you won't be passing any current to speak of.

OR gate. Two inputs. If one OR the other goes high (has voltage) then the output goes high (has voltage). Contrast to an AND gate where both inputs must be high for a high output, and there's also an Exclusive OR, AKA "XOR" which is the same as an OR *EXCEPT* that only ONE input can be high to have a high output. If both inputs are high on an XOR, the output goes low.

There are also negative versions, but we don't need to worry about those for this purpose.

EDIT: Its been a long time - there's a vague chance that the diode won't turn on because of the (presumed) high impedance of your camera enable. If that happens, put a 10K or so resister to ground at the diode cathode.

 

[Wildman]

Yea - the forward drop is a bit high, but shouldn't be a problem (!!) - you'll have less drop anyway because you won't be passing any current to speak of.

OR gate. Two inputs. If one OR the other goes high (has voltage) then the output goes high (has voltage). Contrast to an AND gate where both inputs must be high for a high output, and there's also an Exclusive OR, AKA "XOR" which is the same as an OR *EXCEPT* that only ONE input can be high to have a high output. If both inputs are high on an XOR, the output goes low.

There are also negative versions, but we don't need to worry about those for this purpose.

OK clear as MUD... But similar to a PNP transistor or NPN transistor...

Now back to the decision to use a diode over a relay....

Can you explain why? It's more or less the same amount of wiring. I'm not trying to argue with your recommendation just trying to understand why.
Isn't there a greater chance that the diode would burn out over time?
My reason for doing this is so that I can have that reverse camera on for times like when I have a trailer hooked up so I can watch my load. Which would namely be the Jeep... And to be able to see traffic behind me also. So on a trip where I'm driving 8+ hours a day the camera would be on all this time.

Thanks

 

[Zorba]

OK clear as MUD... But similar to a PNP transistor or NPN transistor...

Now back to the decision to use a diode over a relay....

Can you explain why? It's more or less the same amount of wiring. I'm not trying to argue with your recommendation just trying to understand why.
Isn't there a greater chance that the diode would burn out over time?
My reason for doing this is so that I can have that reverse camera on for times like when I have a trailer hooked up so I can watch my load. Which would namely be the Jeep... And to be able to see traffic behind me also. So on a trip where I'm driving 8+ hours a day the camera would be on all this time.

Thanks

By all means use the relay if that's more familiar/comfortable for you. There's nothing whatsoever wrong with the relay approach in the slightest! It would be easier *for me* to do the diode as its simpler *to me*. Then again - the relay is something you can bolt down somewhere, the diode would either have to be put onto a terminal strip or spliced inline somewhere. I'd say go with the relay at this point, you have it, you understand it, and if it craps out you know how to fix it. You'll be fine.

 

[Wildman]

By all means use the relay if that's more familiar/comfortable for you. There's nothing whatsoever wrong with the relay approach in the slightest! It would be easier *for me* to do the diode as its simpler *to me*. Then again - the relay is something you can bolt down somewhere, the diode would either have to be put onto a terminal strip or spliced inline somewhere. I'd say go with the relay at this point, you have it, you understand it, and if it craps out you know how to fix it. You'll be fine.

I understand both items. I just remember diodes burning out on the generators. But this was 40+ years ago too. It's an electrical item so either one can burn out. I've had relays fail too.
I was just wondering why on your choice. I've got the diodes because I've used them in other circuits I've been working on.

 

[reddvltj]

OK here's how I think it'd be wired if I was using a 5 terminal relay instead of a diode.

Terminal 87 N/O-—--12V Battery Power
Terminal 87A N/C-— Reverse Light 12V
Terminal 30-—————-Camera Power
Terminal 85-—————-Upfitter #2 Switch
Terminal 86-—————-Ground


View attachment 626861

OK guys.... Let me know if my thought process is correct of not. Had to shake out some braincells and clear out some cobwebs.

This way works perfectly! When your factory upfitter switch is in the off position the backup lights will turn the camera on.
When you switch the Upfitter switch on it will disconnect the backup lights from the camera all together absolutely no need for a diode wired in this configuration.


A 5-pin relay (also known as a Single Pole Double Throw or SPDT relay) allows you to switch a circuit between two different paths. It has a common terminal (pin 30) that is connected to either the normally closed (NC) terminal (pin 87a) or the normally open (NO) terminal (pin 87), depending on whether the relay coil (pins 85 and 86) is energized.
To use a 5-pin relay to reverse power flow with two different power sources, you'll need to utilize its switching capability:
1. Connecting the Power Sources:

• Connect the positive terminal of your first power source to pin 87a (normally closed contact).
• Connect the positive terminal of your second power source to pin 87 (normally open contact).
• Connect the negative terminals of both power sources to a common ground.

2. Wiring the Load:

• Connect your load (the device requiring reversed power flow) to pin 30 (the common terminal).
• This configuration allows the 5-pin relay to effectively switch between the two power sources, and if one of them is connected with reversed polarity, the power flow to the load will be reversed when the relay is energized

3. Controlling the Relay:

• Connect pin 85 of the relay coil to the common ground.
• Connect pin 86 of the relay coil to a switch or control signal that will energize the relay when needed.

How it works:

• When the relay coil is de-energized: Pin 30 is connected to pin 87a, so the load receives power from the first power source.
• When the relay coil is energized: Pin 30 switches to connect with pin 87, and the load receives power from the second power source, effectively reversing the power flow (if the second source's polarity is reversed compared to the first)

• Important Considerations:
  • Diode Protection: Consider adding a diode across the relay coil to protect against voltage spikes.
  • Fusing: Ensure both power source circuits are protected with appropriate fuses or circuit breakers.
  • Voltage and Current Ratings: Make sure your relay can handle the voltage and current requirements of your power sources and load.
  • Safety: Be mindful of potential reversed polarity issues, especially when working with different power sources, and follow safety protocols.

 

[Zorba]

I understand both items. I just remember diodes burning out on the generators. But this was 40+ years ago too. It's an electrical item so either one can burn out. I've had relays fail too.
I was just wondering why on your choice. I've got the diodes because I've used them in other circuits I've been working on.

Do remember - diodes on (most) generators are handling high current. Here you're only dealing with micro-amps. Anything can blow up, as we both know all too well! So it really boils down to preference - I'll give the "Elvish Advice" and say both no and yes...

 

[Wildman]

Of course like with EVERY project it seems to take 2-3 times longer than expected... I'd planned on using the trailer battery charge wire as the 12V to power the camera when I'd turned on the upfitter switch... And as it always seems to go I have 0V on the charge wire.... WTF????? So I get out the manual and start checking fuses & replays... Nope all GOOD... So for now I'm chasing that issue....

I'll get the camera wiring done once I figure out this SNAFU.....

 

[Zorba]

Of course like with EVERY project it seems to take 2-3 times longer than expected.

Are you sure we're not related? My projects always seem to take about 4X as long as they should - cue Mr. Scott. My father once bought a truck with a pre-wired trailer connector. The charge line was dead on it too. Turned out, it wasn't connected on the other end - apparently on purpose.

 

[Wildman]

Are you sure we're not related? My projects always seem to take about 4X as long as they should - cue Mr. Scott. My father once bought a truck with a pre-wired trailer connector. The charge line was dead on it too. Turned out, it wasn't connected on the other end - apparently on purpose.

I know it had power 2 years ago when I'd replaced the old taillights and also installed the license plate frame camera. So it DID work....

 

[lBasket]

Of course like with EVERY project it seems to take 2-3 times longer than expected... I'd planned on using the trailer battery charge wire as the 12V to power the camera when I'd turned on the upfitter switch... And as it always seems to go I have 0V on the charge wire.... WTF????? So I get out the manual and start checking fuses & replays... Nope all GOOD... So for now I'm chasing that issue....

I'll get the camera wiring done once I figure out this SNAFU.....

Always something

 

[B1Toad]

I didn't read back in the thread but on some vehicles (my Sprinter is one) the 12 volt power pin at the 7 way does not power up until the "trailer recognition module" sees a trailer plugged in.

 

[Wildman]

I didn't read back in the thread but on some vehicles (my Sprinter is one) the 12 volt power pin at the 7 way does not power up until the "trailer recognition module" sees a trailer plugged in.

I had voltage on the charge wire 2 years ago... I'm sure once I figure it out it'll be something simple...

 

[Wildman]

This way works perfectly! When your factory upfitter switch is in the off position the backup lights will turn the camera on.
When you switch the Upfitter switch on it will disconnect the backup lights from the camera all together absolutely no need for a diode wired in this configuration.


A 5-pin relay (also known as a Single Pole Double Throw or SPDT relay) allows you to switch a circuit between two different paths. It has a common terminal (pin 30) that is connected to either the normally closed (NC) terminal (pin 87a) or the normally open (NO) terminal (pin 87), depending on whether the relay coil (pins 85 and 86) is energized.
To use a 5-pin relay to reverse power flow with two different power sources, you'll need to utilize its switching capability:
1. Connecting the Power Sources:

• Connect the positive terminal of your first power source to pin 87a (normally closed contact).
• Connect the positive terminal of your second power source to pin 87 (normally open contact).
• Connect the negative terminals of both power sources to a common ground.

2. Wiring the Load:

• Connect your load (the device requiring reversed power flow) to pin 30 (the common terminal).
• This configuration allows the 5-pin relay to effectively switch between the two power sources, and if one of them is connected with reversed polarity, the power flow to the load will be reversed when the relay is energized

3. Controlling the Relay:

• Connect pin 85 of the relay coil to the common ground.
• Connect pin 86 of the relay coil to a switch or control signal that will energize the relay when needed.

How it works:

• When the relay coil is de-energized: Pin 30 is connected to pin 87a, so the load receives power from the first power source.
• When the relay coil is energized: Pin 30 switches to connect with pin 87, and the load receives power from the second power source, effectively reversing the power flow (if the second source's polarity is reversed compared to the first)

• Important Considerations:
  • Diode Protection: Consider adding a diode across the relay coil to protect against voltage spikes.
  • Fusing: Ensure both power source circuits are protected with appropriate fuses or circuit breakers.
  • Voltage and Current Ratings: Make sure your relay can handle the voltage and current requirements of your power sources and load.
  • Safety: Be mindful of potential reversed polarity issues, especially when working with different power sources, and follow safety protocols.

A lot better explanation for how the relay works in the setup than I'd of done.
And yes no diode required when using the relay.